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The Science of the Total Environment Jan 2023Light-absorbing aerosols (LAA), including black carbon (BC) and brown carbon (BrC), profoundly impact regional and global climate. Vehicle emission is an important...
Light-absorbing aerosols (LAA), including black carbon (BC) and brown carbon (BrC), profoundly impact regional and global climate. Vehicle emission is an important source of LAA in urban areas, but real-world emission features of LAA from the urban vehicle fleet are not fully understood. This study evaluates traffic-related BC and BrC emission factors (EFs) and their vehicular emission inventories via road tunnel measurements in Tianjin, China, in 2017 and 2021. The distance-based and fuel-based EFs of BC for the mixed fleet were 1.05 ± 1.28 mg km veh and 0.057 ± 0.057 g (kg-fuel), respectively, in 2021, with a dramatic decrease of 80.6 % compared to those in 2017. The BC EFs for gasoline vehicles (GVs, including traditional gasoline and hybrid vehicles) and diesel vehicles (DVs) were 0.55 ± 0.065 mg km veh and 10.5 ± 2.52 mg km veh, respectively, in 2021. Compared to 2017, the BrC EFs also decreased significantly in 2021, by 10.8-53.6 %, with 0.32 ± 0.45 mg km veh and 0.018 ± 0.020 g (kg-fuel) of distance-based and fuel-based EFs for mixed fleet. The BrC EFs for GVs and DVs were 0.091 ± 0.024 mg km veh and 3.06 ± 0.91 mg km veh, respectively, in 2021. Based on the BC and BrC EFs for GVs and DVs and annual mileage for each vehicle category, the annual vehicular LAA emission inventories were estimated. From 2017 to 2021, the annual vehicular LAA emissions in Tianjin have been significantly reduced, by 69 % for BC and 10 % for BrC. DVs account for a small amount of the vehicle population (8.4 %), but contribute to most of the BC (83 %) and BrC (86 %). Our study demonstrates the significant reduction of vehicular light-absorbing aerosols emission due to vehicle pollution prevention and control in China.
Topics: Air Pollutants; Particulate Matter; Gasoline; Environmental Monitoring; Vehicle Emissions; Aerosols; Soot; China; Carbon
PubMed: 36206905
DOI: 10.1016/j.scitotenv.2022.159212 -
Chemosphere Jul 2024Mn or Co supported CeO fiber catalysts were synthesized following a biotemplating route and evaluated in soot combustion and benzene total oxidation. The catalysts were...
Mn or Co supported CeO fiber catalysts were synthesized following a biotemplating route and evaluated in soot combustion and benzene total oxidation. The catalysts were characterized by SEM, EDX, N physisorption, FTIR-ATR, XRD, RAMAN and XPS. SEM results confirmed that the "twisted ribbon" morphology of the biotemplate was mostly maintained. XRD and Raman showed that Mn and Co cations partially insert into ceria lattice and also segregate at the surface of the fibers. XPS allowed to determine that both set of catalysts exhibit Ce and Ce species, in addition to adsorbed and lattice oxygen. Also, the average oxidation state (AOS) of surface Mn could be calculated. Compared to bare Fib Ce, the performances for both reactions were improved for the supported catalysts, except from the catalyst with lowest Mn content for soot combustion. The catalytic activity was discussed in terms of the physicochemical features of the supported catalysts.
Topics: Cerium; Oxidation-Reduction; Benzene; Catalysis; Manganese; Cobalt; Soot
PubMed: 38705410
DOI: 10.1016/j.chemosphere.2024.142247 -
Journal of the Air & Waste Management... Apr 2016A number of literatures have documented adverse health effects of exposure to fine particulate matter (PM2.5), and secondary sulfate aerosol and black carbon may...
UNLABELLED
A number of literatures have documented adverse health effects of exposure to fine particulate matter (PM2.5), and secondary sulfate aerosol and black carbon may contribute to health impacts of PM2.5 exposure. We designed an exposure system to generate sulfate and traffic soot particles, and assessed the feasibility of using it for human exposure assessment in a pilot human exposure study. In the designed exposure system, average mass concentrations of generated sulfate and soot particles were 74.19 μg/m3 and 11.54 μg/m3 in the chamber and did not vary significantly during two-hour human exposure sessions. The size ranges of generated sulfate were largely between 20 to 200 nm, whereas those of generated soot particles were in the size ranges of 50 to 200 nm. Following two-hour exposure to generated sulfate and soot particles, we observed significant increases in fractional exhaled NO (FeNO) in young and health subjects. Building on established human exposure system and health response follow-up methods, future full-scale studies focusing on the effects of mixed particulates and individual PM2.5 components would provide data in understanding the underpinning cardio-respiratory outcomes in relation to air pollution mixture exposure.
IMPLICATIONS
Controlled exposure is a useful design to measure the biological responses repeatedly following particulate exposures of target components and set exposure at target levels of health concerns. Our study provides rational and establishes method for future full-scale studies to focus on examining the effects of mixed particulates and individual PM2.5 components.
Topics: Atmosphere Exposure Chambers; Biomarkers; Blood Pressure; Breath Tests; Healthy Volunteers; Heart Rate; Humans; Inhalation Exposure; Male; Pilot Projects; Soot; Sulfates; Young Adult
PubMed: 26726796
DOI: 10.1080/10962247.2015.1136712 -
Environmental Science & Technology Apr 2021Black carbon (BC) particles contribute to climate warming by heating the atmosphere and reducing the albedo of snow/ice surfaces. The available Arctic BC deposition...
Black carbon (BC) particles contribute to climate warming by heating the atmosphere and reducing the albedo of snow/ice surfaces. The available Arctic BC deposition records are restricted to the Atlantic and North American sectors, for which previous studies suggest considerable spatial differences in trends. Here, we present first long-term BC deposition and radiocarbon-based source apportionment data from Russia using four lake sediment records from western Arctic Russia, a region influenced by BC emissions from oil and gas production. The records consistently indicate increasing BC fluxes between 1800 and 2014. The radiocarbon analyses suggest mainly (∼70%) biomass sources for BC with fossil fuel contributions peaking around 1960-1990. Backward calculations with the atmospheric transport model FLEXPART show emission source areas and indicate that modeled BC deposition between 1900 and 1999 is largely driven by emission trends. Comparison of observed and modeled data suggests the need to update anthropogenic BC emission inventories for Russia, as these seem to underestimate Russian BC emissions and since 1980s potentially inaccurately portray their trend. Additionally, the observations may indicate underestimation of wildfire emissions in inventories. Reliable information on BC deposition trends and sources is essential for design of efficient and effective policies to limit climate warming.
Topics: Air Pollutants; Arctic Regions; Carbon; Environmental Monitoring; Russia; Soot
PubMed: 33769801
DOI: 10.1021/acs.est.0c07656 -
Environmental Pollution (Barking, Essex... Jun 2023A catalyst is usually coated on Diesel particulate filter (DPF) for assisted regeneration. In this paper, the oxidation activity and pore structure evolutions of soot...
A catalyst is usually coated on Diesel particulate filter (DPF) for assisted regeneration. In this paper, the oxidation activity and pore structure evolutions of soot under the effect of CeO are explored. CeO effectively increases the oxidation activity of soot and reduces the initial activation energy; in the meantime, the addition of CeO changes the soot oxidation mode. Pure soot particles tend to produce the porous structure in the oxidation process. Mesopores promote the diffusion of oxygen, and macropores contribute to reduce the agglomeration of soot particles. Additionally, CeO provides the active oxygen for soot oxidation and promotes the multi-point oxidation at the beginning of soot oxidation. With the oxidation proceeding, catalysis causes the collapsion of soot microspatial structures, in the meantime, the macropores caused by the catalytic oxidation are filled by CeO. It results in the tight contact between soot and catalyst, further promoting the formation of the available active oxygen for soot oxidation. This paper is meaningful to analyze the oxidation mechanism of soot under catalysis, which lays a foundation for improving the regeneration efficiency of DPF and reducing the particle emission.
Topics: Soot; Reactive Oxygen Species; Oxygen; Oxidation-Reduction; Catalysis; Dust
PubMed: 37019256
DOI: 10.1016/j.envpol.2023.121540 -
Environmental Pollution (Barking, Essex... Apr 2024Carbon black and cadmium (Cd) are important components of atmospheric particulate matter and cigarette smoke that are closely associated with the occurrence and...
Carbon black and cadmium (Cd) are important components of atmospheric particulate matter and cigarette smoke that are closely associated with the occurrence and development of lung diseases. Carbon black, particularly carbon black nanoparticles (CBNPs), can easily adsorbs metals and cause severe lung damage and even cell death. Therefore, this study aimed to explore the mechanisms underlying the combined toxicity of CBNPs and Cd. We found that the combined exposure to CBNPs and Cd promoted significantly greater autophagosome formation and ferroptosis (increased malonaldehyde (MDA), reactive oxygen species (ROS), and divalent iron ions (Fe) levels and altered ferroptosis-related proteins) compared with single exposure in both 16HBE cells (human bronchial epithelioid cells) and mouse lung tissues. The levels of ferroptosis proteins, transferrin receptor protein 1 (TFRC) and glutathione peroxidase 4 (GPX4), were restored by CBNPs-Cd exposure following treatment with a 3-MA inhibitor. Additionally, under CBNPs-Cd exposure, circPSEN1 overexpression inhibited increases in the autophagy proteins microtubule-associated protein 1 light chain 3 (LC3II/I) and sequestosome-1 (P62). Moreover, increases in TFRC and Fe, and decreases in GPX4were inhibited. Knockdown of circPSEN1 reversed these effects. circPSEN1 interacts with autophagy-related gene 5 (ATG5) protein and upregulates nuclear receptor coactivator 4 (NCOA4), the co-interacting protein of ATG5, thereby degrading ferritin heavy chain 1 (FTH1) and increasing Fe in 16HBE cells. These results indicated that the combined exposure to CBNPs and Cd promoted the binding of circPSEN1 to ATG5, thereby increasing autophagosome synthesis and ATG5-NCOA4-FTH1 axis activation, ultimately inducing autophagy-dependent ferroptosis in 16HBE cells and mouse lung tissues. This study provides novel insights into the toxic effects of CBNPs and Cd in mixed pollutants.
Topics: Humans; Mice; Animals; Cadmium; Soot; Ferroptosis; Autophagy; Epithelial Cells
PubMed: 38365078
DOI: 10.1016/j.envpol.2024.123562 -
The Science of the Total Environment Jun 2022The wildfires of August and September 2020 in the western part of the United States were characterized by an unparalleled duration and wide geographical coverage. A...
The wildfires of August and September 2020 in the western part of the United States were characterized by an unparalleled duration and wide geographical coverage. A particular consequence of massive wildfires includes serious health effects due to short and long-term exposure to poor air quality. Using a variety of data sources including aerosol optical depth (AOD) and ultraviolet aerosol index (UVAI), obtained with the Moderate-Resolution Imaging Spectroradiometer (MODIS), Multi-Angle Implementation of Atmospheric Correction (MAIAC) and Tropospheric Monitoring Instrument (TROPOMI), combined with meteorological information from the European Center for Medium-Range Weather Forecasts (ECMWF) and other supporting data, the impact of wildfires on air quality is examined in the three western US states, California, Oregon, and Washington, and areas to the east. The results show that smoke aerosols not only led to a significant deterioration in air quality in these states but also affected all other states, Canada, and surrounding ocean areas. The wildfires increased the average daily surface concentration of PM posing significant health risks, especially for vulnerable populations. Large amounts of black carbon (BC) aerosols were emitted into the atmosphere. AOD and UVAI exceeded 1 and 2 over most of the country. In parts of the three western states, those values reached 3.7 and 6.6, respectively. Moreover, a reanalysis based on MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, version 2) showed that the maximum values of BC surface mass concentration during the wildfires were about 370 μg/m. These various indicators provide a better understanding of the extent of environmental and atmospheric degradation associated with these forest fires.
Topics: Aerosols; Air Pollutants; Air Pollution; Environmental Monitoring; Particulate Matter; Retrospective Studies; Soot; United States; Wildfires
PubMed: 35218845
DOI: 10.1016/j.scitotenv.2022.154103 -
Veterinary Pathology Jul 2023The body of a deceased human and 4 deceased cats were found in a house while a fire was being extinguished. As a result of these findings, arson, homicide, and animal...
The body of a deceased human and 4 deceased cats were found in a house while a fire was being extinguished. As a result of these findings, arson, homicide, and animal death investigations were opened. As part of the animal death investigation, all of the cats were submitted for veterinary forensic autopsies. All cats had soot on the fur and had soot deposits within the oral cavity, esophagus, and respiratory tract. Two cats had soot within the stomach. Cardiac blood was analyzed for carboxyhemoglobin using a CO-oximeter, and all cats had levels >65%. The cause of death was determined to be due to toxic smoke inhalation from the structure fire. Case findings support the potential use of CO-oximeter for determination of carboxyhemoglobin levels in cats and continued research in this area of forensic practice.
Topics: Cats; Humans; Animals; Homicide; Soot; Carboxyhemoglobin; Firesetting Behavior; Fires; Oximetry; Carbon Monoxide Poisoning; Cat Diseases
PubMed: 37154042
DOI: 10.1177/03009858231170306 -
The Science of the Total Environment Feb 2023In this study, the oxidation behaviors of soot particles from diesel engine when using neat diesel fuel (DF) and lubricating base oil-blended fuel (BBF) were...
In this study, the oxidation behaviors of soot particles from diesel engine when using neat diesel fuel (DF) and lubricating base oil-blended fuel (BBF) were investigated. The changes in the average particle size and nanostructure parameters during soot oxidation process were analyzed. Exhaust particulate matter (PM) samples were collected from a four-stroke, four-cylinder and turbo0charged diesel engine operated under 1200 rpm and 200 Nm. DF and BBF Soot samples with different oxidation weight losses of 20 %, 40 %, and 60 % were obtained by thermogravimetric isothermal oxidation experiments at 600 °C, and the particle size and nanostructure parameters (fringe length, L; fringe tortuosity, T) were characterized using high-resolution transmission electron microscopy (HRTEM). Results show that the DF soot particles exhibited an oxidation mode that was initially dominated by surface oxidation and gradually deviated to internal oxidation. Combustion of the base oil increased the soot internal oxidation tendency. HRTEM results showed that as the soot oxidation progressed, the primary particles showed a shell-core, onion-like and hollow structure gradually. The L of the primary particles gradually increased, and the T gradually decreased, indicating that the soot layer crystallites were rearranged during the oxidation process, which resulted in a disordered nanostructure that transitioned to a more graphitized nanostructure.
Topics: Soot; Vehicle Emissions
PubMed: 36368398
DOI: 10.1016/j.scitotenv.2022.160009 -
Environmental Science & Technology Feb 2022Fossil fuel (FF) combustion emissions account for a large, but uncertain, amount of the soot in the atmosphere, play an important role in climate change, and adversely...
Fossil fuel (FF) combustion emissions account for a large, but uncertain, amount of the soot in the atmosphere, play an important role in climate change, and adversely affect human health. However, historical estimates of FF contributions to air pollution are limited by uncertainties in fuel usage and emission factors. Here, we constrained FF soot emissions from southeastern China over the past 110 years, based on a novel radiocarbon method applied to sedimentary soot. The reconstructed soot accumulations reflect the integrated effects of increased FF use caused by economic development and reductions in emissions due to pollution controls. A sharp increase in FF soot started in 1950 as southeastern China industrialized and developed economically, but decreased FF soot fluxes in recent years suggest that pollution controls reduced soot emissions. We compare FF soot history to changes in CO emissions, industrial and economic activities, and pollution controls and show that FF soot fluxes are more readily controlled than atmospheric CO. Our independent FF soot record provides insights into the effects of economic development and controls on air pollution and the environmental impacts from the changes in soot emissions.
Topics: Carbon; Carbon Dioxide; China; Environmental Monitoring; Fossil Fuels; Humans; Soot
PubMed: 35007066
DOI: 10.1021/acs.est.1c05424